[AMDGPU] Make getInstSizeInBytes more generic

NFC. This check mainly handles size affecting literals. Make it check all
explicit operands instead of a few by name. Also make the isLiteral
check handle the KIMM operands, see https://reviews.llvm.org/D111067

Change-Id: I1a362d55b2a10f5c74d445272e8b7829a8b77597

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D113318

Change-Id: Ie6c688f30a71e0335d1c6dd1ff65019bd7ce684e